Variants of the CTLA4 gene that segregate with autoimmune diseases are not associated with endometriosis

An autoimmune etiology has been suggested for endometriosis mostly on the basis of an increased prevalence of autoimmune diseases in affected women. Cytotoxic T lymphocyte antigen (CTLA) 4 gene is recognized as a primary determinant for autoimmunity since specific polymorphisms have been associated with predisposition to most autoimmune disorders. This study was aimed to evaluate whether two variants of CTLA4 gene might be associated with endometriosis in an Italian population. We examined the +49A/G polymorphism and the CT60A/G dimorphism in n = 146 endometriosis subjects classified according to Holt and Weiss criteria. Controls were represented by n = 165 women without laparoscopic evidence of the disease. We found no statistically significant difference in the genotype frequencies between women with and without endometriosis. The proportion of the mutant G allele of the +49A/G polymorphism in the former and in the latter group resulted 34 and 30%, respectively. The proportion of the susceptible G allele of the CT60 A/G dimorphism resulted 51% in both groups. No association was demonstrated between the polymorphisms and the clinical forms of the disease and no susceptibility haplotypes were found. These findings suggest that endometriosis aetiology is not primarily associated with the development of CTLA4-linked autoimmunity.